HAProxy - Load balancer
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William Lallemand c6221db375
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BUG/MINOR: mworker: don't try to access an initializing process
In pcli_prefix_to_pid(), when resolving a worker by absolute pid
(@!<pid>) or by relative pid (@1), a worker that still has PROC_O_INIT
set (i.e. not yet ready, still initializing) could be returned as a
valid target.

During a reload, if a client connects to the master CLI and sends a
command targeting a worker (e.g. @@1 or @@!<pid>), the master resolves
the target pid and attempts to forward the command by transferring a fd
over the worker's sockpair. If the worker is still initializing and has
not yet sent its READY signal, its end of the sockpair is not usable,
causing send_fd_uxst() to fail with EPIPE. This results in the
following alert being repeated in a loop:

  [ALERT] (550032) : socketpair: Cannot transfer the fd 13 over sockpair@5. Giving up.

The situation is even worse if the initializing worker has already
exited (e.g. due to a bind failure) but has not yet been removed from
the process list: in that case the sockpair's remote end is already
closed, making the failure immediate and unrecoverable until the dead
worker is cleaned up.

This was not possible before 3.1 because the master's polling loop only
started once all workers were fully ready, making it impossible to
receive CLI connections while a worker was still initializing.

Fix this by skipping workers with PROC_O_INIT set in both the absolute
and relative pid resolution paths of pcli_prefix_to_pid(), so that
only fully initialized workers can be targeted.

Must be backported to 3.1 and later.
2026-03-18 17:08:30 +01:00
.github CI: remove redundant "halog" compilation 2026-02-23 11:11:26 +01:00
addons MINOR: promex: export "haproxy_sticktable_local_updates" metric 2026-03-18 11:18:37 +01:00
admin BUG/MINOR: admin: haproxy-reload rename -vv long option 2026-03-08 01:37:56 +01:00
dev DEV: gdb: add a new utility to extract libs from a core dump: libs-from-core 2026-03-18 15:30:39 +01:00
doc MINOR: debug: read all libs in memory when set-dumpable=libs 2026-03-18 15:30:39 +01:00
examples MINOR: mailers: warn if mailers are configured but not actually used 2025-06-27 16:41:18 +02:00
include MINOR: debug: read all libs in memory when set-dumpable=libs 2026-03-18 15:30:39 +01:00
reg-tests MINOR: jwt: Manage ec certificates in jwt_decrypt_cert 2026-03-10 14:58:47 +01:00
scripts SCRIPTS: git-show-backports: add a restart-from-last option 2026-03-09 15:36:05 +01:00
src BUG/MINOR: mworker: don't try to access an initializing process 2026-03-18 17:08:30 +01:00
tests TESTS: quic: add unit-tests for QUIC TX part 2025-09-08 14:49:03 +02:00
.cirrus.yml CI: cirrus-ci: bump FreeBSD image to 14-3 2025-10-09 14:06:48 +02:00
.gitattributes MINOR: Configure the cpp userdiff driver for *.[ch] in .gitattributes 2021-02-22 18:17:57 +01:00
.gitignore MINOR: tevt/dev: Add term_events tool 2025-01-31 10:41:50 +01:00
.mailmap DOC: update Tim's address in .mailmap 2021-09-16 09:14:14 +02:00
.travis.yml MEDIUM: mworker: remove USE_SYSTEMD requirement for -Ws 2024-11-20 12:07:38 +01:00
BRANCHES DOC: clarify the experimental status for certain features 2025-10-17 18:41:13 +02:00
BSDmakefile BUILD: makefile: commit the tiny FreeBSD makefile stub 2023-05-24 17:17:36 +02:00
CHANGELOG [RELEASE] Released version 3.4-dev6 2026-03-05 15:55:28 +01:00
CONTRIBUTING CLEANUP: assorted typo fixes in the code and comments 2025-04-02 11:12:20 +02:00
INSTALL MINOR: version: mention that it's development again 2025-11-26 16:11:47 +01:00
LICENSE LICENSE: add licence exception for OpenSSL 2012-09-07 13:52:26 +02:00
MAINTAINERS MAJOR: spoe: Let the SPOE back into the game 2024-05-22 09:04:38 +02:00
Makefile DEV: gdb: add a new utility to extract libs from a core dump: libs-from-core 2026-03-18 15:30:39 +01:00
README.md DOC: remove openssl no-deprecated CI image 2026-02-19 10:39:23 +01:00
SUBVERS BUILD: use format tags in VERDATE and SUBVERS files 2013-12-10 11:22:49 +01:00
VERDATE [RELEASE] Released version 3.4-dev6 2026-03-05 15:55:28 +01:00
VERSION [RELEASE] Released version 3.4-dev6 2026-03-05 15:55:28 +01:00

HAProxy

alpine/musl AWS-LC Illumos NetBSD FreeBSD VTest

HAProxy logo

HAProxy is a free, very fast and reliable reverse-proxy offering high availability, load balancing, and proxying for TCP and HTTP-based applications.

Installation

The INSTALL file describes how to build HAProxy. A list of packages is also available on the wiki.

Getting help

The discourse and the mailing-list are available for questions or configuration assistance. You can also use the slack or IRC channel. Please don't use the issue tracker for these.

The issue tracker is only for bug reports or feature requests.

Documentation

The HAProxy documentation has been split into a number of different files for ease of use. It is available in text format as well as HTML. The wiki is also meant to replace the old architecture guide.

Please refer to the following files depending on what you're looking for:

  • INSTALL for instructions on how to build and install HAProxy
  • BRANCHES to understand the project's life cycle and what version to use
  • LICENSE for the project's license
  • CONTRIBUTING for the process to follow to submit contributions

The more detailed documentation is located into the doc/ directory:

License

HAProxy is licensed under GPL 2 or any later version, the headers under LGPL 2.1. See the LICENSE file for a more detailed explanation.